Care to explain? I believe for Redis, "appendfsync everysec" is the default. The poster's point was that MySQL and Postgres both ship with something like "appendfsync always", and you have to opt-in to the the less safe mode if you want to get more performance. Redis ships with the less safe mode pre-selected, and so has higher performance out-of-the-box.
You're right. The Postgres equivalent to "appendfsync always" is "synchronous_commit = on". Which AFAIK is the default.
However, one of the nice things about redis is that even if you run "appendfsync everysec" you never run the risk of corruption. You're only risk is losing a maximum of 2 seconds worth of data.
